The total extract obtained from workup of grape seeds contains a number of metabolites, particularly catechin and epicatechin monomers, related proanthocyanidole oligomers and polymers (procyanindins), as well as polymers and high molecular weight tannins.
EP 275224 discloses a process for the preparation of phospholipid complexes of Vitis vinifera flavonoids.
WO 2005/36988 discloses a process for the extraction of Vitis vinifera seeds consisting in the separation of the skin from the seeds immediately after the workup of the extract. The resulting extracts are characterized by a low content in monomeric polyphenols.
EP 348781 discloses fractions enriched in procyanidol oligomers obtained by extraction of Vitis vinifera seeds with ethers or esters or mixtures of esters with aromatic hydrocarbons and/or by filtration.
EP 1035859 discloses the use of phospholipid complexes of extracts of Vitis vinifera for the treatment and the prevention of atherosclerosis.
The known processes have some drawbacks, such as the use of toxic solvents or the need of specific plants or complex procedures.
There is therefore the need of a convenient process, which is industrially carried out in a easy way and provides extracts whose contents in active components may be adjusted at will.